The present invention relates generally to a sorting machine and more particularly to a machine for sorting items such as dragees (sugar-coated pills), other pills, capsules, or candy of varying sizes with high efficiency.
In devices presently known, products of this type are sorted by machines which jolt the products from a supply funnel by means of a vibration conveyor onto long, cylindrical inclined pairs of shafts or chutes with different directions of rotation. The shafts or chutes have a larger diameter at the upper end than at the lower end thereof. As a result, after sliding on these pairs of shafts, the items to be sorted will fall through depending upon their thickness. Items of desired shape or size are again conveyed by means of vibration action over perforated strainers in order to control the sorting in accordance with diameter. Products of a desired size must cover a long sliding distance on the tracks.
The items are subsequently conducted over several sorting belts so that various operating personnel may undertake visual control of the surface. During this control process, there must be especially identified defects located on the surface of the type which during packaging would potentially cause crushing and consequent destruction of the products, such defects being of the type which cannot be detected during control of the thickness of the items. It will be apparent that such defect detection is especially important with regard to pharmaceutical products such as dragees, pills, tablets or the like which could become useless or even dangerous if crushed or otherwise rendered defective.
Because of the repeated vibration during conveyance, these sorting machines tend to create a noise level which is excessive for operating personnel. Therefore, in many cases the sorting machines are arranged in individual enclosures separately from the sorting belts. Additionally, sorting accuracy depends upon the inclination of a pair of shafts which must be repeatedly adjusted depending upon the curvature of the product. If the products are significantly curved and if the shafts are adjusted too steeply, then incorrect measurements cannot be avoided. The surfaces must be visually checked by the operating personnel and due to human characteristics such as fatigue after long intensive control over several hours, accuracy and consistency cannot be maintained even by changes in operating personnel.
The invention includes among the advantages provided thereby the prevention of health hazards to operating personnel by reduction in noise levels, sometimes by as much as 100%, while at the same time enabling high sorting output. Adjustability during product change need not occur at the expense of sorting accuracy and the invention aims to accomplish achievement of completely mechanical control of the sorting which may replace the visual control otherwise required.